Saddle Pads and Rubbing girths

So here’s the list:
Saddle Pads I purchased a new M. Tolouse Marielle about five months ago. I LOVE it! It is literally the only saddle that would accommodate my (apparently) freakishly long femur. The leather is soft, supple, and super grippy. My only issue is that I am significantly tall(5’10"), with really long legs, so I ride in a 18". The billets are pretty long- My horse wears a 22 or 20" girth, and they kinda rub my horse’s side. How can I pad this to prevent rubbing?
Also: My saddle leaves no border around it no matter what pad is under it, it swallows the pad whole. Should I be concerned with the saddle touching her back? Where can I get larger pads(only an inch or two more on spine, maybe three in width and 3-4 in depth. The saddle is that big.)

Any suggestions are great, thanks so much!

For extra padding or length, we have used western pads, that come in all kinds of thickness and shapes, some square, some rounded.

We had a very swaybacked jumper, he was born like that, we were training and showing with a regular double hospital fleece western pad, the regular English one and the English saddle on top of that and he was very sound and comfortable in that.

I have an 18.5 in saddle and use this pad and there is plenty of room

It has held up well.

Also a lot of dressage pads are longer front to back. They are also longer top to bottom too which may help with the girth rubs.

Have you seen these?

Ogilvy makes saddle pads that are not only beautiful quality, but also sized. My BF rides in a 18" extra forward saddle - the Ogilvy pads are the only ones which - in a size large - leave a nice border around and actually fit the saddle.

Lovely pads.

To prevent girth rubs, put on a bit of Body Glide (on the horse, not you, ha).